The invention discloses a high-antibacterial low-emission automotive modified polypropylene composite material and a preparation method thereof. The modified polypropylene is mainly composed of the following components: 1-5 parts of nano zinc dioxide antibacterial functional masterbatch, 60-90 parts of conventional polypropylene, 5-40 parts of porous calcium silicate, 8-20 parts of an elastomer, 0.1-1.5 parts of an antioxidant, and 0-3 parts of other auxiliary agents. According to the composite material and method provided by the invention, the porous calcium silicate particles, the nano zincoxide with high-efficiency antibacterial properties and the conventional polypropylene are subjected to blend extrusion through a twin-screw extruder or an injection molding machine, the extruded strip mixture is cooled by circulating water, the cooled material enters a pelletizer, pelletizing is performed, and therefore the modified polypropylene particles are obtained, wherein the nano zinc oxide gives high-efficiency long-lasting antibacterial ability to the modified polypropylene because the nano zinc oxide easily generates active oxygen; and at the same time, the porous calcium silicate gives excellent comprehensive mechanical properties to the modified polypropylene because the porous calcium silicate has a uniform particle size and chemical stability, especially, the porous characteristic of the porous calcium silicate effectively ''captures'' small-molecular substances and unpleasant odor produced by degradation of the polypropylene during the adsorption extrusion process, andthe porous calcium silicate gives the low-odor low-emission characteristics to the modified polypropylene.